PREDIN: Pregnancy and Vitamin D Intervention Study

NCT ID: NCT05329428

Last Updated: 2025-11-26

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 105 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-04-14
• Study Completion Date: 2024-09-16

Brief Summary

Vitamin D deficiency is common among certain risk groups in Sweden, and occurs approximately in every tenth pregnant woman.The aim of the randomized double-blind controlled trial Pregnancy vitamin D intervention (PREDIN) is to investigate the dose of vitamin D supplementation required in achieving vitamin D sufficiency (25OHD ≥50 nmol/l) in pregnant women at risk of vitamin D deficiency. In addition, the investigators aim to examine if the overall vitamin D status and vitamin D intake have increased since the expanded vitamin D fortification program was initiated in year 2020.

Detailed Description

The effect of maternal vitamin D in pregnancy for maternal and offspring health needs to be clarified. In observational studies, the investigators and others show associations between poor maternal vitamin D status in pregnancy and an increased risk of pregnancy complications. Poor maternal vitamin D status is also linked to impaired growth in the first year of life, and potentially also to higher risk of developing obesity in childhood. Risk factors for vitamin D deficiency in Swedish pregnant women are related to lower intake of vitamin D and to less sun exposure.

Since the evidence for positive effects of maternal vitamin D status or intake is limited, vitamin D interventions in pregnancy are warranted to clarify the causal effects of vitamin D in pregnancy and the doses required to achieve sufficient vitamin D status in deficient women. In the first trimester, pregnant women will be screened at a routine visit in the antenatal care for the risk of vitamin D deficiency using a validated questionnaire. Women who are classified as having a high risk of vitamin D deficiency will be randomized to one of three study arms: usual antenatal care, 20 µg vitamin D per day or 40 µg vitamin D per day. The participants will be followed up until delivery. Blood will be collected for analysis of vitamin D status (25OHD) at screening and in the third trimester of pregnancy. Information regarding pregnancy, gestational complication and fetal growth will be retrieved from medical records after delivery. About 500 women will be screened and their vitamin D status and vitamin D intake will be compared to a previous population-based cohort study, to investigate if the status or intake of vitamin D has increased since the expanded food fortification program was introduced.

The study hypothesis is that vitamin D status and/or vitamin D intake is related to risk of developing complications during pregnancy or delivery and that maternal supplementation with vitamin D during pregnancy will be effective in achieving vitamin D sufficiency in pregnant women at risk of vitamin D deficiency. In addition, the investigators hypothesize that the expanded vitamin D food fortification program has increased the vitamin D status and vitamin D intake of pregnant women in Gothenburg since 2013-2014.

Conditions

Vitamin D Deficiency; Vitamin D3 Deficiency; Pregnancy Complications

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: DOUBLE

Study Groups

Vitamin D Supplementation 20 µg/day

Dietary supplements containing 20 µg of vitamin D per day will be provided to study subjects.

Group Type: EXPERIMENTAL

Vitamin D Supplementation 20 µg/day

Intervention Type: DIETARY_SUPPLEMENT

At a routine visit at the antenatal care in early pregnancy (gestational week \<15) women will be provided with with vitamin D3 (cholecalciferol) supplements. Two tablets, with a total content of 20 µg (800 IE), are taken daily throughout pregnancy.

Vitamin D Supplementation 40 µg/day

Dietary supplements containing 40 µg of vitamin D per day will be provided to study subjects.

Group Type: EXPERIMENTAL

Vitamin D Supplementation 40 µg/day

Intervention Type: DIETARY_SUPPLEMENT

At a routine visit at the antenatal care in early pregnancy (gestational week \<15) women will be provided with with vitamin D3 (cholecalciferol) supplements. Two tablets, with a total content of 40 µg (1600 IE), are taken daily throughout pregnancy.

Usual Antenatal Care

Women randomized to usual antenatal care will receive advise about vitamin D supplementation according to usual antenatal care routines.

Group Type: ACTIVE_COMPARATOR

Usual Antenatal Care

Intervention Type: OTHER

In early pregnancy (gestational week \<15) women are advised by the regular midwife to take a daily supplement of Vitamin D throughout pregnancy, according to usual antenatal care routines.

Interventions

Vitamin D Supplementation 20 µg/day

At a routine visit at the antenatal care in early pregnancy (gestational week \<15) women will be provided with with vitamin D3 (cholecalciferol) supplements. Two tablets, with a total content of 20 µg (800 IE), are taken daily throughout pregnancy.

Intervention Type: DIETARY_SUPPLEMENT

Vitamin D Supplementation 40 µg/day

At a routine visit at the antenatal care in early pregnancy (gestational week \<15) women will be provided with with vitamin D3 (cholecalciferol) supplements. Two tablets, with a total content of 40 µg (1600 IE), are taken daily throughout pregnancy.

Intervention Type: DIETARY_SUPPLEMENT

Usual Antenatal Care

In early pregnancy (gestational week \<15) women are advised by the regular midwife to take a daily supplement of Vitamin D throughout pregnancy, according to usual antenatal care routines.

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• pregnant women in gestational week <15

Exclusion Criteria

• multi-fetal pregnancy
• known disorder to the metabolism of vitamin D, calcium or phosphate (e.g. adrenal gland disorders, kidney disease)
• ongoing treatment with vitamin D of ≥10 µg/day
• difficulties understanding the study information

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: No

Sponsors

Vastra Gotaland Region

OTHER_GOV

Sponsor Role: collaborator

Göteborg University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Hanna Augustin, Ass Prof

Role: PRINCIPAL_INVESTIGATOR

Göteborg University

Locations

Antenatal Care

Gothenburg, , Sweden

Countries

Sweden

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

2021-03871

Identifier Type: -

Identifier Source: org_study_id